CN101821118A

CN101821118A - Tire

Info

Publication number: CN101821118A
Application number: CN200880111004.XA
Authority: CN
Inventors: 小盐真寿; 中村浩一
Original assignee: Bridgestone Corp
Current assignee: Bridgestone Corp
Priority date: 2007-10-10
Filing date: 2008-10-08
Publication date: 2010-09-01
Anticipated expiration: 2028-10-08
Also published as: WO2009048078A1; KR20100056554A; JP5276008B2; JPWO2009048078A1; CN101821118B; KR101085345B1

Abstract

A heavy duty pneumatic radial tire which can reduce second rib punch partial wear without spoiling wet performance and heating durability. In a rib type tread pattern pneumatic radial tire where four main grooves (1) extending along the circumference of a tire are arranged in the tread portion and five rows of land (2a-2e) are formed in the tread portion by the main grooves (1), the second rows of land (2b, 2d) from the outermost ends in the width direction of the tire out of the rows of land (2a-2e) are provided with lug grooves (5a, 5c) extending in the width direction thereof and having raised bottoms (5a', 5c') formed by raising the bottom of the groove toward the surface of the land at the end on the shoulder side, and sipes (6) are formed in the shoulder side edges of the lands (2b, 2d) at such an interval as equalizing the width direction rigidity along the circumference of the tire in regions one third from the land on the shoulder side.

Description

Tire

Technical field

The present invention relates to be suitable for being installed in the Pneumatic belt tire that uses on the vehicles such as truck, city motor bus, particularly in this tire, can alleviate unavoidable in the past generation irregular wear (2nd (second) bar shaped corrugated irregular wear) effectively.

Background technology

As the Pneumatic belt tire that is installed on the heavy-duty vehicles such as truck, city motor bus, to compare driven nature poor with the air-inflation tyre with block-type tread, but straight line stability, polishing machine are good, so, air-inflation tyre below in the past the use more, this air-inflation tyre is separated with many grooves along the circumferential extension of tire of compartment of terrain configuration on the Width of tyre surface, and has the tread contour of dividing the bar shaped pattern type of formation grounding parts waiting each other of above-mentioned many grooves.

But, for this air-inflation tyre, compare and can wear and tear in advance with other grounding parts from Width outermost end second grounding parts of tire, can't avoid the so-called second bar shaped corrugated irregular wear, require to alleviate this irregular wear.

About this point, proposition has following technology, that is, on the tire shoulder side edge part of the bar shaped decorative pattern of an inboard that is positioned at tire shoulder bar shaped decorative pattern, be provided with circumferential continuous stria, form the slice shape decorative pattern that has with the bar shaped decorative pattern main body equal height of dividing by this stria along tire.(for example, with reference to patent documentation 1)

Patent documentation 1: Japanese kokai publication hei 5-246213 communique

; above-mentioned technology in the past is by making the wearing and tearing of slice shape decorative pattern selectively; thereby the technology of the irregular wear when suppressing initial wear is difficult to form the state that till the wear on tyres later stage whole zone of tire width direction keeps uniform wear always.

In addition, in order to alleviate the second bar shaped corrugated irregular wear, it is favourable not forming the cros-rib tread groove that has along the marginal element that the Width of tire extends at this grounding parts (the second bar shaped decorative pattern), but in this case, because can't avoid the reduction of wetland performance, heating durability, so the useful method of can not saying so.

Summary of the invention

Problem of the present invention is to provide a kind of new heavy duty to reuse Pneumatic belt tire, in the air-inflation tyre of tread contour with bar shaped pattern type, can alleviate the inevitable in the past second bar shaped corrugated irregular wear, can form up to use the later stage to make the whole zone of tire width direction carry out uniform wear always.

The present invention is that Pneumatic belt tire is reused in a kind of heavy duty of tread contour of bar shaped pattern type, be provided with along at least three major troughs of the circumferential extension of tire at fetus face, be listed as at the grounding parts that forms on this fetus face more than four row by above-mentioned major trough, it is characterized in that, in above-mentioned grounding parts row, be provided with the cros-rib tread groove from the grounding parts of the Width outermost end secondary series of tire, this cros-rib tread groove extends along the Width of the grounding parts of above-mentioned secondary series, and, has the protruding bottom that bottom land swells towards the grounding parts surface in the end of tire shoulder side, tire shoulder side edge part at this grounding parts is arranged with tire sipe, and this tire sipe makes the Width rigidity in zone of this grounding parts tire shoulder side 1/3 along the circumferential formation uniform state of tire.

At this, about the cros-rib tread groove, so-called " Width along grounding parts extends " is meant with the circumferential development length of tire and compares that the development length of tire width direction is long.

Reuse in the Pneumatic belt tire 15～25% of width preferred above-mentioned protruding bottom, that on the Width of this grounding parts, be of a size of this grounding parts in the heavy duty that forms above-mentioned formation.

In addition, above-mentioned protruding bottom has 60～100% bump height of the groove depth of cros-rib tread groove, the bar number of above-mentioned major trough is four, the width of the grounding parts of this secondary series is 1.0～1.1 times of width of grounding parts that are positioned at the Width central portion of tire, and the grounding parts that is positioned at the tire width direction outermost end has 1.2～1.4 times width of the grounding parts that is positioned at the Width central portion.

In addition, angle of inclination protruding bottom, circumferential with respect to tyre surface of preferred cros-rib tread groove is 70～90 ° a scope, and the bending part more than the place preferably is set in being provided with this cros-rib tread groove of protruding bottom.

In addition, in above-mentioned any tire, preferably in the cross section of the tread width direction of the outermost tire shoulder major trough that is positioned at the tread width direction, at the tire shoulder major trough, and and the inboard adjacent inboard major trough of the tread width direction of this tire shoulder major trough between the grounding parts near surface part of cell wall of the grounding parts side of being divided with respect to the angle of this grounding parts normal to a surface direction, less than the cell wall of this grounding parts side than this grounding parts near surface part near the angle of the inside side's side part in the footpath of the inside side's side in footpath with respect to this grounding parts normal to a surface direction, in this case, the grounding parts near surface part of 25～30% the scope that plays the tire shoulder major trough degree of depth from the grounding parts surface that makes above-mentioned cell wall is with respect to the angle of grounding parts normal to a surface direction, different with the inside side's side part in footpath than this inside side's side in close footpath of grounding parts near surface part of above-mentioned cell wall with respect to the angle of grounding parts normal to a surface direction, the grounding parts near surface of preferred above-mentioned cell wall part is the value in 0～7 ° the scope with respect to the above-mentioned angle of grounding parts normal to a surface direction, above-mentioned cell wall be value in 10～20 ° the scope near the inside side's side part in the footpath of the inside side's side in footpath than this grounding parts near surface part with respect to the above-mentioned angle of grounding parts normal to a surface direction.

Be provided with the cros-rib tread groove from the grounding parts of the Width outermost end secondary series of tire, this cros-rib tread groove extends along the Width of the grounding parts of above-mentioned secondary series, and, have the protruding bottom of bottom land towards the grounding parts surface elevation in the end of tire shoulder side, tire shoulder side edge part at this grounding parts is formed with tire sipe, this tire sipe configuration space make this grounding parts tire shoulder side 1/3 the zone the Width rigidity along tire circumferentially evenly, thereby make the rigid uniformization of the grounding parts at this position, do not damage the wetland performance, heating durability ground alleviates the second bar shaped corrugated irregular wear.

Description of drawings

Fig. 1 is that planar view is launched in the part of the tread contour of expression Pneumatic belt tire of the present invention.

Fig. 2 is the figure in the X-X cross section of presentation graphs 1.

Fig. 3 is the figure of the relation of expression rigid circumference and circumferential position.

Fig. 4 is the figure of expression another embodiment of the present invention.

Fig. 5 is the amplification sectional elevation of middle ground portion.

Fig. 6 is the amplification cross-sectional plane of tire shoulder major trough.

Description of reference numerals

1, major trough; 1a, cell wall; 2a～2e, grounding parts; 3, tire shoulder portion; 4, sidewall portion; 5a～5c, cros-rib tread groove; 5a ', 5c ', protruding bottom; 6, tire sipe; 9, dogleg section; 10, stone release portion; 11, protruding bottom; E, tyre surface bottom; θ, angle of inclination; E, length; D, highly; W, grounding parts width; H, cros-rib tread groove depth; D, the major trough degree of depth; α, β, angle; ρ, grounding parts near surface part.

The specific embodiment

Below, use accompanying drawing to more specifically describe the present invention.

Fig. 1 is that planar view is launched in the part of the tread contour of expression embodiments of the present invention, and Fig. 2 is the figure in the X-X cross section of presentation graphs 1.

Reference numeral 1 expression in the accompanying drawing is formed on the tyre surface tread, and four major troughs in the figure of the circumferential extension of tire, Reference numeral 2a～2e divides to be formed at major trough 1 each other, and at the outermost tire shoulder major trough 1 of tread width direction and the grounding parts between the tyre surface lateral margin, Reference numeral 3 is tyre surface tire shoulder portions, Reference numeral 4 is to be communicated with the sidepiece separately of fetus face, and radius vector is the sidewall portion of side's extension inwardly, Reference numeral 5a～5c is respectively formed on grounding parts 2b～2d, and extend, and along each cros-rib tread groove that circumferentially this grounding parts 2b～2d is demarcated of tire along the Width of this grounding parts 2b～2d.

At this, so-called " tyre surface tread ", be meant mounting of tyre on the wheel rim that is suitable for, and under the state of the air pressure that is filled with regulation, with this tire with the vertical position rest configuration on flat board, and when applying with the corresponding load of quality stipulated to this tire, tire and the dull and stereotyped face that contacts.

In this case, so-called " wheel rim that is suitable for ", be meant size according to tire, by the wheel rim of following prescribed by standard, so-called " air pressure of regulation " is meant in following standard, corresponding with the maximum load ability and the regulation air pressure, so-called maximum load ability is meant and tire is allowed the quality of the maximum that applies in following standard.In addition, so-called " quality of regulation " is meant above-mentioned maximum load ability.

In addition, said here air also can replace with non-active gas or other gases such as nitrogen.

In addition, so-called standard, be meant at the regional actv. industrial standard of producing or use tire, for example be " the YEAR BOOK of THE TIRE AND RIM ASSOCIATIONINC. " in the U.S., being " the STANDARDS MANUAL of THE European Tyre and RimTechnical Organisation " in Europe, is Japanese car tire association " JATMA YEAR BOOK " in Japan.

In above-mentioned grounding parts 2a～2e, from cros-rib tread groove 5a, the 5c of grounding parts 2b, the 2d of the Width outermost end secondary series of tire, its groove depth is constant, and have the bottom land that extends with the outside face almost parallel ground of grounding parts, being provided with in the end of tire shoulder side and making bottom land is that d and the length on the Width of

grounding parts

2b, 2d are protruding bottom 5a ', the 5c ' of e towards the height of

grounding parts

2b, 2d surface elevation.

In addition, Reference numeral 6 is tire sipes of being located at the tire shoulder side edge part of grounding parts 2b, 2d.This tire sipe 6 is configured with interval t, make this

grounding parts

2b, 2d tire shoulder side 1/3 the zone Width rigidity along tire circumferentially evenly.

The inevitable second bar shaped corrugated irregular wear that is produced in the air-inflation tyre of the tread contour with bar shaped pattern type is produced by following situation: the initial stage that is beginning to travel, on the second bar shaped decorative pattern, produce toe and heel wearing and tearing, afterwards, wearing and tearing develop into the side of entering into from the side of pedaling out of tire shoulder side, and then develop into reverse wearing and tearing, in order to suppress the second bar shaped corrugated irregular wear, eliminating toe and heel worn-down starting point is special actv., as its method, at the grounding parts 2b of secondary series, the last setting of 2d has protruding bottom 5a ', the cros-rib tread groove 5a of 5c ', 5c.

If the height d of protruding bottom 5a ', 5c ' is low, then can't improve the rigidity at this position fully, can't embody the effect of bringing by protruding bottom is set, so the bump height of protruding bottom 5a ', 5c ' is preferably 60～100% the scope of the groove depth h of cros-rib tread groove.

In addition, if length e protruding bottom, the grounding parts Width is short, then the rigidity of protruding bottom is low excessively, might produce the crack at this, on the other hand, on the contrary under the long situation of this length e, the marginal element of extending along the Width of tire becomes very few, can't avoid the reduction of wetland performance, thus the length e of protruding bottom be preferably grounding

parts

5a, 5c width W 15～25%.

For example by following formula obtain grounding parts, (length with grounding parts is 1 to Width rigidity G, calculate the rigidity of each unit), as shown in Figure 3, as long as so that the Width rigidity in the zone of the tire shoulder side 1/3 of this

grounding parts

2b, 2d is provided with the interval t (it is constant making sectional area) of tire sipe 6 along the circumferentially uniform mode of tire, thus, can seek the uniformization of grounding parts rigidity of the tire shoulder side of the second bar shaped decorative pattern.Consider that interval t is provided with the incision length S (with reference to Fig. 1) of tire sipe 6.

Formula 1

G = 2 K \cdot E \cdot \frac{{bL}^{3}}{H^{3}} \frac{1}{(1 + 3.9 \frac{L^{2}}{H^{2}})}

G: the shear rigidity (N/mm) before and after the piece

L: block length (length between the tire sipe) (mm)

B: piece width (mm)

H: tile height (mm)

E:0.36 * (being suitable for 100% modulus of rubber)/(100% modulus of standard rubbers) (MPa)

K: coefficient of correction

When the bar number of above-mentioned major trough is four, the width of preferred this

grounding parts

2b, 2d is 1.0～1.1 times of width of grounding parts 2c that are positioned at the Width central portion (on the equatorial plane) of tire, and the width that is positioned at grounding parts 2a, the 2e of tire width direction outermost end is 1.2～1.4 times of the width of the grounding parts 2c that is positioned at Width central portion (on the equatorial plane).

Its reason is, the input of the side force of the Width outermost end of tire is bigger than the input of Width central portion side force, so the width of grounding parts 2a, the 2e of the Width outermost end of tire is the wideest, next order by the grounding parts 2c of this

grounding parts

2b, 2d, central portion in turn is provided with width, can make each grounding parts rate of wear even.

Fig. 4 is the part sectional view of the Width of the local expansion drawing of tread contour of expression another embodiment of the present invention and tire.

At this, be formed with four major troughs 1 that extend continuously along circumferential linearly at the tyre surface tread, between above-mentioned major trough and between the outermost tire shoulder major trough 1 and tyre surface lateral margin E in the tread width direction, master plan is told the grounding parts 2a～2e of five row, at the 2c of center-point earth portion, along circumferentially be separated with the compartment of terrain form many in the drawings to the upper right side to extend steppedly, and cross the ladder cros-rib tread groove 5b of the 2c of this center-point earth portion fully, in addition, at each 2b of middle ground portion that is positioned at center-point earth portion 2c adjacent position, 2d, form many bending cros-rib tread groove 5a along circumferentially being separated with the compartment of terrain, 5c, these many bending cros-

rib tread groove

5a, 5c is at this central authorities' major trough 1 opening, from this opening part to upper right or all linearly extensions in angle of inclination to left down circumferentially to equate with respect to tyre surface, and, near zone from outermost tire shoulder major trough 1, the groove edge of tire shoulder major trough 1 for example, once be bent into roughly " ヘ word shape " with the width in 50～70% the scope of middle ground portion width W, and to this tire shoulder major trough 1 opening.

At this, angle of inclination dogleg section 9, circumferential with respect to tyre surface of each bending cros-rib tread groove 5a, the 5c that forms at each 2b of middle ground portion, 2d can also be made as mutual different angle except all being made as the identical angle like that as shown.And, be each bending cros-

rib tread groove

5a, 5c in the drawings in place bending, also can be with each bending cros-

rib tread groove

5a, 5c in the bending of a plurality of positions.In addition, Reference numeral 10 expression is made of the square protrusion of the bottom land that is formed on central major trough 1 among the figure, prevent that stone from embedding the stone release portion of usefulness.

And, at this, in the tire shoulder major trough one side part of each bending cros-

rib tread groove

5a, 5c, form the protruding bottom 11 make the bottom land protuberance and to form, tilt angle theta line of centers, circumferential with respect to tyre surface that makes each protruding bottom 11 or this each protruding bottom 11 is in 70～90 ° the scope.

At this bending cros-

rib tread groove

5a, 5c can prevent the irregular wear of tire shoulder side end, and, can guarantee the length of cros-rib tread groove and make tire have excellent wetland performance, in addition, bending cros-rib tread groove 5a, the above-mentioned tilt angle theta of 5c has been guaranteed the cros-rib tread groove significantly, the Width of tire and circumferential marginal element, realize excellent wetland performance, in addition, in order to prevent by cros-

rib tread groove

5a, 5c is at grounding parts 2b, formation becomes the acute angle corner portions of the core of irregular wear easily in the 2d, at this above-mentioned tilt angle theta is selected in 70～90 ° scope.

Even increase the tilt angle theta of cros-rib tread groove,, just can guarantee θ=70～90 ° as long as bending part is set by mode with the core that do not form irregular wear.

Promptly, the angle of inclination circumferential with respect to tyre surface of protruding bottom 11 is in 70～90 ° the scope, by further raising bending cros-

rib tread groove

5a, 5c, between the cros-rib tread groove of the opening portion of tire shoulder major trough 1 rigidity of part, thereby can further prevent from effectively partly to produce bar shaped corrugated irregular wear at this grounding parts.

This angle of inclination less than 70 ° situation under, can't be with bending cros-rib tread groove 5a, the rigidity of the acute angle corner portions of the grounding parts of the opening portion of 5c is brought up to desired degree, and carry out irregular wear as core with this acute angle corner portions, so at bending cros-rib tread groove 5a, protruding bottom 11 is set on the 5c, seek the uniformization of the Width rigidity of grounding parts part, in addition, with cros-rib tread groove 5a, the open end portion of 5c produces bar shaped corrugated irregular wear as core, even in the bump height of protruding bottom 11 is under 100% the situation of cros-rib tread groove depth, also because protruding bottom weares and teares gradually through using, so can produce bar shaped corrugated irregular wear equally.

This protruding bottom 11 also as described above, as the cross-sectional view of the illustrative middle ground 2b of portion of Fig. 5,2d, the Width of preferred this

grounding parts

2b, 2d, size e is in 15～25% the scope of width W of the 2b of middle ground portion, 2d, and in 60～100% the scope of the groove depth h of rake 9 protruding bottom 11, that from the bump height d of bottom land be bending cros-

rib tread groove

5a, 5c.

And in this tire, edge portion in tire shoulder major trough 1 side of the 2b of middle ground portion, 2d, set many tire sipe 6 that broad ways is extended with the posture of extending, the mode that in this grounding parts, stops to the Width of grounding

parts

2b, 2d, the Width rigidity that this tire sipe of many 6 makes zone this grounding

parts

2b, 2d, tire shoulder side 1/3 tyre surface week upwards evenly.

Setting at interval also as described above of the tire sipe 6 of this situation, particularly at the bending cros-rib tread groove 5a that is applied to be provided with protruding bottom 11, under the situation of 5c, if uniformly-spaced to form tire sipe 6, grounding parts 2b then, the Width rigidity of 2d is at bending cros-

rib tread groove

5a, 5c's, part diminishes near the open end of tire shoulder major trough 1 opening, on tyre surface Zhou Fangxiang, become inhomogeneous, so about the bending cros-rib tread groove Width rigidity of portion part indirectly, can be based on above-mentioned (formula 1), obtain from the rigidity of tire shoulder major trough 1 side in 1/3 scope of the width of this grounding parts part, by so that this Width rigidity is determined bending cros-rib tread groove portion's Width rigidity partly indirectly at the interval that the uniform mode that makes progress in tyre surface week is set tire sipe.

In addition, in position shown in Figure 4, except the edge portion of central major trough 1 side of the 2b of middle ground portion, 2d, also form the short

size tire sipe

13,14 that extends along the grounding parts Width respectively in two edge portions of center-point earth portion 5, these

tire sipes

13,14 are in the present invention not necessarily.

But, as shown in Figure 4, divide on the tyre surface tread by four major troughs 1 in the tire of grounding parts 2a～2e that five row are arranged, also as described above, the width of the preferred 2b of middle ground portion, 2d is in 1.0～1.1 times the scope of width of the 2c of center-point earth portion, and the width that is divided in outermost tire shoulder grounding parts 2a, the 2e of tread width direction is in 1.2～1.4 times the scope of width of the 2c of center-point earth portion.

In addition, preferably, in the tread width direction cross section of tire shoulder major trough 1, as Fig. 6 with as illustrated in the amplification view, the grounding parts near surface of the cell wall 1a of the 2b of middle ground portion, 2d side part is with respect to the angle α of the 2b of middle ground portion, 2d normal to a surface n direction, than the cell wall 1a of the 2b of middle ground portion, 2d side partly to compare the radially inner side part of more close radially inner side little with respect to the angle β of the 2b of middle ground portion, 2d normal to a surface n direction with the grounding parts near surface.

Thus, near rigidity part tire shoulder major trough 1 of the 2b of middle ground portion, 2d is reduced, this part easy deformation when loading of tire rotates, part is is roughly worn and torn equably along the circumferential integral body of tire near making this, can be suppressed near this part thus more effectively and produce bar shaped corrugated irregular wear.

But, make that cell wall 1a's play grounding parts near surface part p in 25～30% the scope of depth D of tire shoulder major trough 1 with respect to the angle of grounding parts normal n from the grounding parts surface, different with the inside side's side part in footpath of cell wall 1a with respect to the inside side's side in the close footpath of this grounding parts near surface part p, preferred grounding parts near surface part p with respect to this angle α of grounding parts normal n less than the angle β of the inside side's side part in its footpath with respect to grounding parts normal n, more preferably grounding parts near surface part p is 0～7 ° with respect to the angle α of grounding parts normal n, and the inside side's side part in its footpath is 10～20 ° with respect to the angle β of grounding parts normal n.

Like this, by making above-mentioned angle α, grounding parts near surface part p and the footpath inside side side part of this grounding parts near surface part p of β in 25～30% scope of the depth D that plays the tire shoulder major trough from the grounding parts surface is different, the inside side's side in footpath at this grounding parts near surface part p partly increases under the situation of angle, utilize the reduction of the rigidity of grounding parts part, can tackle effectively at worn-down initial stage grounding parts near surface and produce toe and heel wearing and tearing.

In addition, at this, making grounding parts near surface part p is 25～30% scope of tire shoulder major trough depth D, and irregular wear becomes problem especially in the time of in above-mentioned scope.

Grounding parts near surface part p is 25% o'clock less than tire shoulder major trough depth D, owing to can't cover the generation scope of irregular wear fully, the possibility that produces irregular wear is arranged still.

With respect to this, if greater than 30%, then do not worry irregular wear basically, than 30% darker degree of depth part, can seek the uniformization of rigidity of grounding parts of the both sides of tire shoulder major trough 1, suppress wearing and tearing preferably.

That is, when in greater than 30% scope of tire shoulder major trough depth D the cell wall angle being applied relative mistake, wearing and tearing become and carry out easily, and wear-out life reduces.

And, this above-mentioned angle α, β are made as the grounding parts near surface be in 0～7 ° the scope value, be more remarkable under the situation in 10～20 ° the scope than grounding parts near surface by the part of the inside side's side in footpath.

Embodiment 1

Make following tire, promptly, (well width is 13mm to have four major troughs, the degree of depth is 15mm), the width of second grounding parts is 32mm, the well width of cros-rib tread groove is 3mm, the degree of depth is 3mm, the height d of protruding bottom is 3mm, the length e of protruding bottom is 5mm, (length of protruding bottom)/(the width w of second grounding parts) is 16%, (the height d of protruding bottom)/(the cros-rib tread groove depth h of second grounding parts) is 100%, and, with interval 9.6mm (t1), 12.6mm (t2) the configuration A/F is 2.5mm, the degree of depth is the tire sipe of 13mm, and bar shaped decorative pattern width be distributed as the C/L of tyre surface central authorities: second: the tire shoulder side is the TBR tire (being fit to tire) of 1: 1.05: 1.24 size 11R22.5, attach it to and be of a size of on 8.25 * 22.5 the wheel rim, interior pressure is made as 800kPa, carry out the irregular wear characteristic, the wetland performance, the test of heating durability, carried out (not having protruding bottom with in the past tire, tire sipe is spaced apart 9.4mm uniformly-spaced, and is in addition identical with suitable tire) relatively investigation.

In addition, for the irregular wear characteristic, with above-mentioned mounting of tyre on the car that reality is used, make it behind about 50000km that travels on the asphalt road, height residual quantity with the bar shaped corrugated irregular wear of second grounding parts compares, the above-mentioned mounting of tyre that the wetland performance is identical is on the car that reality is used, brake on being covered with the road surface of iron plate, travelling with 20km/h, compare with its stopping distance, in addition, for the heating durability, above-mentioned tire is carried out indoor testing drum (be suitable for the diameter of cylinder of cylinder: 1.707m, speed: 65km/h, load: standard 100% during beginning, every 6h increase respectively normal loading 10%), it is travelled up to producing fault, the used time is compared.

Its result, confirm as follows: for irregular wear, under the situation of tire in the past, the height residual quantity is 3mm, finds to produce bar shaped corrugated irregular wear in being fit to tire.In addition, for the wetland performance, tire, suitable tire all were 100% in the past, did not have big difference; For the heating durability, under the situation of tire in the past, be 32 hours, suitable tire is 33 hours, and can keep this performance.

Embodiment 2

For the embodiment tire that is of a size of TBR295/80R22.5 and comparative example tire I～III, anti-irregular wear, wetland performance and heating durability test have been carried out respectively.

The embodiment tire has tread contour as shown in Figure 4, the 2b of middle ground portion, the width W of 2d is 33mm, bending cros-rib tread groove 5a, the degree of depth h of 5c is 2mm, the tilt angle theta circumferential with respect to tyre surface of protruding bottom 11 is 75 °, at above-mentioned bending cros-rib tread groove 5a, 5c's, position apart from tyre surface central portion side 20.8mm is provided with " ヘ word shape " bending part, protruding bottom 11, grounding parts 2b, the length e of the Width of 2d is 5mm, this length e's of protruding bottom 11, ratio with respect to middle ground portion width W is 15%, the bump height d of protruding bottom 11 is 2mm, this height d's, ratio with respect to tipper degree of depth h is 100%, and, the 2b of middle ground portion, 2d's, the tire sipe of the lateral margin of all groove 1 sides of tire shoulder is spaced apart 10.3mm and (does not separate cros-rib tread groove 5a, the part of 5c9) and 13.7mm (separate cros-rib tread groove 5a, the part of 5c), the A/F of each tire sipe 6 and length are respectively 2.5mm and 10mm, and each grounding parts 2c, 2b-2d, the width of 2e is central authorities: the centre: the tire shoulder side is 1: 1.05: 1.36.

And, as Fig. 6 with shown in the solid line, the cell wall 1a of major trough 1 with respect to the angle of grounding parts normal n at grounding parts near surface part p less than the angle of the inside side's side part in footpath with respect to grounding parts normal n.

More specifically, in position shown in Figure 6, D is that 16.3mm, p are that 5.0mm, α are 5.0 °.

Comparative example tire 1 has and embodiment tire identical construction except the protruding bottom angle of inclination circumferential with respect to tyre surface is 30 ° of these points.

Comparative example tire 2 has and embodiment tire identical construction except the tire sipe of the lateral margin of the tire shoulder major trough side of middle ground portion is this point of 10.1mm at interval.

Comparative example tire 3 is not except being provided with protruding bottom on bending cros-rib tread groove, and the dogleg section of the above-mentioned cros-rib tread groove angle of inclination circumferential with respect to tyre surface be outside 30 ° of these points, has and embodiment tire identical construction.

At this, each tire sets installed on 9.00 * 22.5 the wheel rim, and fill the air pressure of 850kPa, be installed on the car of actual use, behind the 50000km that travels on the asphalt road, measurement is estimated anti-irregular wear in toe and heel wear height residual quantity that middle ground portion produces.

In addition, under these conditions with each mounting of tyre on the car that reality is used, be covered with on the road surface of iron plate, measure the speed of a motor vehicle from 20km/h to the stopping distance that stops, the wetland performance is estimated.

In addition, under these conditions each tire is used for indoor cylinder (diameter: 1.707m) experimental engine, make it carry out load with the speed of 65km/h and roll, obtain the time till producing fault, the heating durability is estimated.

In addition, for loading of tire, be by 100% of the maximum load ability of JATMA prescribed by standard in the zero hour, whenever increase by 10% through 6 hours load.

Above-mentioned test results is illustrated in table 1.

Table 1

	The embodiment tire	Comparative example tire 1	Comparative example tire 2	Comparative example tire 3
	The embodiment tire	Comparative example tire 1	Comparative example tire 2	Comparative example tire 3	Anti-irregular wear	Do not have	??2mm	??2mm	??3mm
Wetland performance (numerical value is the smaller the better)	??100	??102	??102	??100	Anti-irregular wear	Do not have	??2mm	??2mm	??3mm
	??100	??102	??102	??100	Heating durability (time)	??33	??32	??33	??31

According to table 1 as can be known, the embodiment tire can be guaranteed excellent wetland performance and heating durability, and can improve anti-irregular wear performance effectively.

Claims

1. a tire is the tire with tread contour of bar shaped pattern type, is provided with along at least three major troughs of the circumferential extension of tire at fetus face,, it is characterized in that at the grounding parts row that form on this fetus face more than four row by above-mentioned major trough,

In above-mentioned grounding parts row, be provided with the cros-rib tread groove from the grounding parts of the Width outermost end secondary series of tire, this cros-rib tread groove extends along the Width of the grounding parts of above-mentioned secondary series, and, have the protruding bottom of bottom land towards the grounding parts surface elevation in the end of tire shoulder side

Tire shoulder side edge part at the grounding parts that is provided with this cros-rib tread groove is arranged with tire sipe, and the Width rigidity in zone that this tire sipe makes this grounding parts tire shoulder side 1/3 circumferentially is uniform state along tire.

2. tire according to claim 1,

Above-mentioned protruding bottom, the size on the Width of this grounding parts be this grounding parts width 15～25%.

3. tire according to claim 1 and 2,

Above-mentioned protruding bottom has 60～100% bump height of the groove depth of cros-rib tread groove.

4. according to each described tire of claim 1～3,

The bar number of above-mentioned major trough is four, the width of above-mentioned grounding parts is 1.0～1.1 times of width of grounding parts that are positioned at the Width central portion of tire, and the grounding parts that is positioned at the tire width direction outermost end has 1.2～1.4 times width of the grounding parts that is positioned at the Width central portion.

5. according to each described tire of claim 1～4,

The protruding bottom of the cros-rib tread groove angle of inclination circumferential with respect to tyre surface is 70～90 ° scope.

6. according to each described tire of claim 1～5,

Bending part more than one place is set in being provided with the cros-rib tread groove of protruding bottom.

7. according to each described tire of claim 1～6,

Cross section in the tread width direction of the outermost tire shoulder major trough that is positioned at the tread width direction, the tire shoulder major trough and and the inboard adjacent inboard major trough of the tread width direction of this tire shoulder major trough between the grounding parts near surface part of cell wall of the grounding parts side of being divided with respect to the angle of this grounding parts normal to a surface direction, less than the cell wall of this grounding parts side than this grounding parts near surface part near the angle of the inside side's side part in the footpath of the inside side's side in footpath with respect to this grounding parts normal to a surface direction.

8. tire according to claim 7,

The grounding parts near surface part of 25～30% the scope that plays the tire shoulder major trough degree of depth from the grounding parts surface that makes above-mentioned cell wall is with respect to the angle of grounding parts normal to a surface direction, more different with respect to the angle of grounding parts normal to a surface direction near the inside side's side part in the footpath of the inside side's side in footpath than this grounding parts near surface part with above-mentioned cell wall.

9. according to claim 7 or 8 described tires,

The grounding parts near surface of above-mentioned cell wall part is the value in 0～7 ° the scope with respect to the above-mentioned angle of grounding parts normal to a surface direction, above-mentioned cell wall be value in 10～20 ° the scope near the inside side's side part in the footpath of the inside side's side in footpath than this grounding parts near surface part with respect to the above-mentioned angle of grounding parts normal to a surface direction.